Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754629Ab2JNPGp (ORCPT ); Sun, 14 Oct 2012 11:06:45 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46312 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754525Ab2JNOme (ORCPT ); Sun, 14 Oct 2012 10:42:34 -0400 Message-Id: <20121014143549.160935001@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 14 Oct 2012 15:37:27 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Hugh Dickins , Sasha Levin , Mel Gorman , Rik van Riel , Johannes Weiner , Michel Lespinasse , Ying Han , Linus Torvalds Subject: [ 114/147] mm: fix invalidate_complete_page2() lock ordering In-Reply-To: <20121014143533.742627615@decadent.org.uk> X-SA-Exim-Connect-IP: 77.75.106.1 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2550 Lines: 70 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hugh Dickins commit ec4d9f626d5908b6052c2973f37992f1db52e967 upstream. In fuzzing with trinity, lockdep protested "possible irq lock inversion dependency detected" when isolate_lru_page() reenabled interrupts while still holding the supposedly irq-safe tree_lock: invalidate_inode_pages2 invalidate_complete_page2 spin_lock_irq(&mapping->tree_lock) clear_page_mlock isolate_lru_page spin_unlock_irq(&zone->lru_lock) isolate_lru_page() is correct to enable interrupts unconditionally: invalidate_complete_page2() is incorrect to call clear_page_mlock() while holding tree_lock, which is supposed to nest inside lru_lock. Both truncate_complete_page() and invalidate_complete_page() call clear_page_mlock() before taking tree_lock to remove page from radix_tree. I guess invalidate_complete_page2() preferred to test PageDirty (again) under tree_lock before committing to the munlock; but since the page has already been unmapped, its state is already somewhat inconsistent, and no worse if clear_page_mlock() moved up. Reported-by: Sasha Levin Deciphered-by: Andrew Morton Signed-off-by: Hugh Dickins Acked-by: Mel Gorman Cc: Rik van Riel Cc: Johannes Weiner Cc: Michel Lespinasse Cc: Ying Han Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/truncate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/truncate.c b/mm/truncate.c index 75801ac..f38055c 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -394,11 +394,12 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return 0; + clear_page_mlock(page); + spin_lock_irq(&mapping->tree_lock); if (PageDirty(page)) goto failed; - clear_page_mlock(page); BUG_ON(page_has_private(page)); __delete_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/